Method and composition for bleaching milling products



' Patented July 16, 1940 UNITED STATES METHOD AND GOIWPOSITION FOR BLEACH- ING MILLING PRODUCTS Frederic H. Penn, Dallas, Tex.

' N Drawing." Application April 5, 1940, Serial N0. 328,151

10 Claims.

My invention relates to the treatment of wheat flour and other milling products and more particularly has reference to the bleaching of flour and the like by means of non-flammable organic peroxide compositions.

Organic peroxides, notably benzoyl peroxide, derived from hydrogen peroxide, have long been used as bleaching agents for flour. They are quite flammable and decomposable in the presence of a spark, flame or temperatures above 105 C. and are even explosive under certain conditions. Therefore, considerable caution has been necessary in the handling of these flammable organic peroxides.

To prepare organic peroxides for the bleaching of flour, it is necessary that the organic peroxide be in a dry finely divided form, in order to be intimately mixed with the flour. To accomplish fine grinding, the organic peroxide is ordinarily mixed with an equal amount of an inert material, such as dicalcium phosphate, calcium sulfate, or the like, and then ground to the desired fineness. Although these inert materials prevent the decomposition of the organic peroxides during the grinding process, they have no efiect on the flammability of the organic peroxides.

Many attempts have been made to prepare non-flammable o'ganic peroxide compositions such as would effect a complete bleach of the hour when added, thereto. None of these attempts has been successful, because the materials used to prevent flammability were in such large amounts that the bleaching efiect of the organic peroxides was not sufficient to completely bleach flour without employing inordinately large quantitles of the composition, or the method of preparation did not permit the necessary time grinding of the organic peroxides, or the organic peroxides were prepared in such manner as to be susceptible to packing or caking.

An object of this invention is to provide nonflammable organic peroxide compositions in dry powdered form.

Another object of the invention resides in the provision of non-flammable organic peroxide compositions of high bleaching power.

Liquid peroxides, as acetyl peroxides, or inactive peroxides, as phthalyl peroxides, are not suitable for the purpose of this invention. The peroxides intended for use in the present invention are the so-called active organic peroxides, these being primarily the aromatic and fatty acid peroxides which have suficient activity in powdered form to accomplish at least a 90% flour bleach. The active organic peroxides of the type mentioned are the ones which are particularly objectionable because of flammability.

The dry powdered flour bleaching composition of the present invention comprises, in addition to the active organic peroxide, 8. water soluble alkali aluminum sulfate containing about twenty-four (24) moles of water of crystallization. In the preferred embodiment of the invention, the composition additionally contains magnesium carbonate to facilitate fine grinding and to prevent caking and packing of the composition. Other fillers may also be used, such as tricalcium phosphate, calcium carbonate, although magnesium carbonate has been found preferable for grinding the peroxide-"sulfate mixture without matting or calring.

Benzoyl peroxide is the preferred peroxide to use as the active organic peroxide, but other active aromatic peroxides, as cinnamoyl peroxide and phenyl acetyl peroxide, and fatty acid peroxides, as lauryl peroxide and stearyl peroxide, may also be used with the alkali aluminum sulfate and magnesium carbonate.

As illustrative of the preparation of the pre- H ferred non-flammable organic peroxide composition, one hundred (100) grams of dry benzoyl peroxide, seventy (70) grams of dry potassium aluminum sulfate, and thirty grams of magnesium carbonate are mixed together and ground to a finely divided powder. The resultant product is non-flammable, non-explosive, and is ready for use as a flour bleaching agent. Instead of aluminum potassium sulfate, other compounds containing about twenty-four (24) moles of water of crystallization' may be used, such as ammonium aluminum sulfate or sodium aluminum sulfate.

Potassium aluminum sulfate in the amount of about by weight of the composition is sufficient to prevent flammability of the organic peroxides. The amount of benzoyl peroxide should always be about by weight of the total composition. Magnesium carbonate, in the amount of about 15% by weight of the total composition, is sufiicient to facilitate thefine grinding of the benzoyl peroxide and potassium aluminum sulfate mixture, and to prevent the packing and caking of the composition.

In practicing the flour bleaching method of this invention, the non-flammable benzoyl peroxide, potassium aluminum sulfate, magnesium carbonate composition is fed directly into the flour stream at any convenient point during the milling operation, and intimately mixed with the flour by means of powder feeding machines now in general use in the mills, in the proportion of about on'e-half ounce to one barrel (196 lbs.) of flour. For thorough distribution of such small amounts of the bleaching composition in the noun the composition should be in the form of a dry free-flowing finely divided powder. A satisfactory bleaching is obtained by exposing the flour to the action of the bleaching composition for about twenty-four (24) hours.

In the appended claims I have characterized the peroxides as active and having substantial flour bleaching properties, in order to distinguish from those organic peroxides which are of insuflicient activity and bleaching power to effect a commercial bleach. By substantial flour bleaching properties is meant the ability to bleach flour satisfactorily for commercial purposes, that is, to effect more than a 90% bleach.

I claim:

11A flour bleaching composition comprising a I dry free flowing powdered mixture of an active organic peroxide having substantial flour bleaching properties, a water soluble alkali aluminum sulfate containing, per mole, about twenty-four (24) moles of water of crystallization, in sufficient amount to prevent flammability of the organic peroxide, and magnesium carbonate.

2. A flour bleaching composition comprising a dry free flowing powdered mixture of an active organic peroxide having substantial flour bleaching properties, potassium aluminum sulfate containing, per mole, about twenty-four (24) moles of water of crystallization, in sufficient-amount to prevent flammability of the organic peroxide, and magnesium carbonate.

3. A flour bleaching composition comprising a dry free flowing powdered mixture of benzoyl peroxide, a water soluble alkali aluminum sulfate, containing, per mole, about twenty-four (24) moles of water of crystallization, in suflicient amount to prevent flammability of the benzoyl peroxide, and magnesium carbonate.

4. A flour bleaching composition comprising a dry free flowing powdered mixture of benzoyl peroxide, potassium aluminum sulfate, containing, per mole, about twenty-four (24) moles of water of crystallization, in suflicient amount to prevent flammability of the benzoyl peroxide, and magnesium carbonate.

5. A method for bleaching. wheat flour and other milling products, which comprises mixing with the dry milling product a dry free flowing powdered mixture of an active organic peroxide having substantial bleaching properties and a water soluble alkali aluminum sulfate containing, per mole, about twenty-four (24) moles of water of crystallization, the peroxide being in suflicient amount to bleach the milling product and said sulfate being in suflicient amount to prevent flammability of the peroxide, and subjecting the milling product in dry form to the action of said mixture for a suificient time to bleach the milling product.

6. A method for bleaching wheat flour and other milling products, which comprises mixing with the dry milling product a dry free flowing powdered mixture of an active organic peroxide having substantial bleaching properties, magne- 5 sium carbonate and potassium aluminum sulfate containing per mole, about twenty-four (24) moles of water of crystallization, the peroxide being in suflicient amount to bleach the milling product ,and said sulfate being in suflicient 0 amount to prevent flammability of the active organic peroxide, and subjecting the milling product in dry formto the action of the said mixture for a suflicient time to bleach the milling product.

7. A method for bleaching wheat flour and 15 other milling products, which comprises mixing with the dry milling product a'dry free flowing powdered mixture of benzoyl peroxide, magnesium carbonate and a water soluble alkali aluminum sulfate containing, per mole, about 29 twenty-four (24) moles of water of crystallization, the peroxide being in sufficient amount to bleach the milling product and said sulfate being in sufficient amount to prevent flammability of the benzoyl peroxide, and subjecting the milling 25 product to the action of said mixture for a sufficient time to bleach the milling product.

8. A method for bleaching wheat flour and other milling products, which comprises mixing with the dry milling product a dry free flowing 3o powdered mixture of benzoyl peroxide, magnesium carbonate and potassium aluminum sulfate containing, per mole, about twenty-four (24) moles of water of crystallization, the peroxide being in suflicient amount to bleach the milling product and said sulfate being in sufficient amount to prevent flammability of the benzoyl peroxide, and subjecting the milling product in dry form to the action of said mixture for a sufiicient time to bleach the milling product.

9. A flour bleaching composition comprising a dry free flowing powdered mixture of an active organic peroxide having substantial bleaching properties, a water soluble alkali aluminum sulfate containing, per mole, about twenty-four moles of water of crystallization, in sufiicient amount to prevent flammability of the active organic peroxide, and a dry free flowing powdered filler.

10. A method for bleaching wheat flour and other milling products, which comprises mixing with the dry milling product a dry free flowing powdered mixture of an activeorganic peroxide having substantial bleaching properties, a water soluble alkali aluminum sulfate containing, per 5 mole, about twenty-four moles of water of crystallization, in sufficient amount to prevent flammability of the active organic peroxide, and a dry free flowing powdered filler, and subjecting the milling product in dry form to the action of said mixture for a suflicient time to bleach the milling product.

' FREDERIC H. PENN. 

